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OCR
§ The question of balance in the biocoenosis | 51 domesticated animals cause the same changes as the activity of corrumpent elements such as grasshoppers, or a herd of bison, as both select plants that cannot tolerate repeated heavy grazing or increased nitrogen load. Who doubts, however, that the background of such animal activity is the biocoenosis? Who claims that the plant cover that is transformed by animal activities was not “in equilibrium’, or was no longer a biocoenosis? From the criteria listed, humans should be considered a natural phenomenon, as any other population, and their exclusion from the biocoenosis is not reasonable (Glen, 1954). Is it justified to insert the criterion of equilibrium in the concept of biocoenosis? According to a clear majority of authors, yes. Bertalanffy (1949) shows that open systems (and every biocoenosis must be considered such) cannot achieve an equilibrium sensu stricto, and he uses the term “Fliessgleischgewicht” (lit. “flow balance”) to characterise their stationary state. Poljakov and Sumakov (1940), Pavlovszky and Novikov (1950), as well as Jermy (1955), deny the link between biocoenosis and equilibrium. We agree with them. The biocoenosis does not come into being from the existence of a never-before-defined, and to-be-verified equilibrium, but is a correlative unity of its structural elements. It is undeniable, though, that in the life of a biocoenosis, there is something that creates the impression of order, some sort of harmonic cooperation between the structural elements, with some form of hidden organising principle. The existence of this underlying influence is noticed when something goes awry in the life of a biocoenosis, and the usual order is upset (Dudich 1939). What can this organising principle be that, from the authors’ perspective, creates the mirage of an equilibrium? If there is such an order, it can only manifest itself by showing, at every level, a gain in relation to the level above. There has to be an excess of producent elements, otherwise the consuments cannot fit in, nor survive, in the long term, and both must produce a surplus to accommodate intercalary and reducent elements into the coenosis. However, the existence of the producents, with increased demand of resources, is inconceivable without the activity of the soil-living organisms. Plants that evolved on humus-rich soils cannot live on rock faces where there is room only for lichens. The organising or evolutionary principle, therefore, depends on the interaction of the members, and it is manifested so that, once a member is in place, it not only makes possible the addition of the next member, but also exerts an influence on the previous one. The first corrumpent, intercalary and reducent elements assume the pre-existence of the first producent, but they, in turn, generate further changes to life conditions because, in relation to each other, they introduce new environmental factors (Schwenke, 1953). The enriched life conditions allow the insertion of new producents, with the result of further differentiation in the complexity of conditions, preparing for the arrival of further elements. This is how the biocoenosis develops and
